The Submachine (meaning "submerged machines") games is a series of point and click, "escape from the room" puzzle games where the player must find objects and clues scattered throughout various settings, figure out what to do with them, and apply them to certain objects and circumstances to open up more areas of each game and to hopefully eventually beat the games.

Basically all the player (who is never shown onscreen) has to do is use the mouse to search for onscreen items and clues and click on them in order to place them somewhere or store them into their inventory for later use, or to press a button or move a lever, switch or other device to perform a function that will help the player solve the mysteries of the game.

The Loop

This Submachine entry is totally different from the previous two games in the series.

It isn't made clear how the player arrives in this area as it is. There are almost no items to collect at all in this game; just one at the beginning and another one at the very end. Like the name implies, it's a giant loop: the player is in an unending loop of corridors, as they can move straight up, down, left or right, and the corridors will never end. This is also the only Submachine game where the player can die at the end if they perform the wrong action in the final area.

Supposedly in a showdown against the Submachine itself, the player must solve a series of puzzles in this maze of corridors. Some involve manipulating various machines, levers and buttons found in the corridors or on machines, and others are in regards to the map itself that is usually found not far from the player's starting point in a level. Some of the puzzles that are needed to solve to advance to the next level include moving to certain coordinates and activating a lever found there, reproducing patterns projected on a wall with devices, and turning all levers in a level, among others.

The game ends by the player either incorrectly taking the wrong action in the last level and dying, or by collecting one last object and taking it to a statue (?), which warps them to The Lab...Submachine 4.

Notes

This is the only Submachine game ever made so far where it has passwords as a save feature, as the other Submachine games either don’t have a save feature or they are automatic.